Web guide roller assembly

ABSTRACT

A web guide roller assembly for guiding a traveling web in which the web guide roller is rotatably mounted on followers located internally of the roller, the followers defining a guide bearing slidably and nonrotatably engaging longitudinally arcuate portions of a guide bar that extends through the roller to thereby support the roller for longitudinal shifting and tilting movement relative to the path of web travel. An operator for longitudinally shifting the roller relative to the guide bar is advantageously located internally of the roller and operatively connected to the guide bar and one of the followers.

United States Patent [191 Ott, Jr.

[ 54] WEB GUIDE ROLLER ASSEMBLY [75] Inventor: Robert W. Ott, Jr., Rockford, Ill.

[73] Assignee: Rockford Servo Corporation,

Rockford, Ill.

[22] Filed: Aug. 13, 1971 [21] Appl. No.: 171,573

[52] US. Cl ..226/19 [51] Int. Cl. ..B65h 25/26 [58] Field of Search ..226/19, 20-23, 226/179, 180

[56] References Cited UNITED STATES PATENTS 2,643,116 6/1953 Hasselquist ..226/19 X 3,490,674 1/1970 Ott ..226/19 [451 May 8,1973

Prirriary Examiner-Richard A. Schacher Attorney-McCanna, Morsbach, Pillote & Muir [57] ABSTRACT A web guide roller assembly for guiding a traveling web in which the web guide roller is rotatably mounted on followers located internally of the roller, the followers defining a guide bearing slidably and nonrotatably engaging longitudinally arcuate portions of a guide bar that extends through the roller to thereby support the roller for longitudinal shifting and tilting movement relative to the path of web travel. An operator for longitudinally shifting the roller relative to the guide bar is advantageously located internally of the roller and operatively connected to the guide bar and one of the followers.-

11 Claims, 5 Drawing Figures SHEET 2 [IF 2 PATENTEB W 81973 WEB GUIDE ROLLER ASSEMBLY BACKGROUND OF THE INVENTION Web guide apparatus have heretofore been made which support the web guide roller for combined longitudinal shifting and tilting movement of the web guide roller relative to the path of travel of the web. Longitudinal shifting movement of the web roller in a direction transverse to the path of web travel, and opposite the direction of deviation of the web from the desired path, produces a relatively rapid correction of the path of travel of. the web. However, if the factors which initially caused the web to move out of the desired path continue to exist, the web will tend to creep back out of position. Tilting of the web guide roller as it is moved longitudinally applies a continuous correction to the traveling web and thus tends to maintain the traveling web on the corrected path. While the relationship between the longitudinal movement of the roller and the tilting movement of the roller will vary in different installations depending on factors such as the width of the web, speed of web travel, web tension, friction between the web and guide roll, and stiffness of the web, it is frequently desirable to have the tilting of the web occur about a relatively large instantaneous arc center, frequently of the order of the width of the web and more.

In the web guide apparatus disclosed in the U. S. Pat. to Robert W. Ott, Jr. No. 3,390,823, patented July 2, 1968, a web guide roller is rotatably mounted on a support base and the support base is mounted by followers that slidably engage arcuate guide bars having. a common arc center to support the roller for combined longitudinal shifting and tilting movement relative to the path of web travel. In the web guide apparatus disclosed in that patent, the followers and guide bars are laterally offset from the axis of the roller to one side of the roller. In order to provide a stable support it has been the practice to utilize two or more guide bars and followers at each end of the roller spaced apart in a direction radially of the arc center of the guide bars. Web guide apparatus have also been made which utilize a single guide bar having arcuate end portions, with the guide bar extending through the web guide roller, but with the followers located outwardly of the ends of the roller. In the last-mentioned apparatus, the center of the followers was laterally offset from the axis of the roller so that lateral forces applied to the roller, due to web tension and/or other forces applied to the web, produced a force couple which tended to cause the follower to twist relative to the guide bar and bind. Accordingly, such prior apparatus were adapted for use only in installations where the lateral forces on the roller were relatively low. In addition, the abovedescribed web guide apparatus wherein the followers were located either at the side of the web guide rollers or outwardly of the ends of the rollers, required clearance at either the sides or ends of the rollers to accommodate the followers.

SUMMARY OF THE INVENTION The present invention relates to an improved web guide roller assembly wherein a support bar extends through the roller and has end portions extending oblique to the roller axis and wherein the followers are located internally of the roller and rotatably connected thereto at locations such that the axis of the roller intersects the guide bearings. With this arrangement, the center of the guide bearing in the follower is adjacent the roller axis to minimize the tendency of the follower to twist and bind on the guide bar. In addition, arranging of the followers internally of the roller minimizes the space required externally of the roller for mounting the roller assembly. The operator for effecting relative movement between the roller and guide bar is advantageously located internally of the roller and connected through passages in the guide bar to a power source.

An important object of this invention is to provide a web guide roller assembly-which supports the roller for longitudinal shifting and tilting movement relative to the path of web travel and which is capable of supporting the roller against relatively high lateral forces on the roller caused by web tension and/or other forces acting on the traveling web.

Another object of this invention is to provide a web guide roller assembly which occupies a minimum of space externally of the roller.

An important feature of this invention resides in the provision of a web guide roller assembly wherein an arcuate motion guide bar extends through the roller and guide bar followers and bearings are located internally of the roller at a location such that the axis of the roller intersects the guide bearing.

These, together with other objects and advantages .of the present invention will be better understood from the following description when taken in connection with the accompanying drawings wherein:

FIG. 1 is a diagrammatic view of a web guide apparatus embodying the web guide roller of the present invention;

FIG. 2 is a fragmentary perspective view of one end of the web guide roller assembly of FIG. 1;

FIG. 3 is a longitudinal sectional view through the web guide roller assembly;

FIG. 4 is a transverse sectional view taken on the plane 4-4 of FIG. 3 showing the parts on a larger scale; and

FIG. 5 is a fragmentary end elevational view of the web guide roller assembly of FIG. 1.

The web guide roller assembly of the present invention is generally adapted for guiding traveling webs and may be used either with webs of indeterminate length as well as so-called endless type webs such as belts and the like. The web guide roller asembly in general includes a roller 10 adapted for running engagement with a web W; a support bar 11 adapted for mounting on a stationary support and extending through the hollow roller; a follower means 13 slidably mounted on the roller, and bearings 14 rotatably mounting the roller on the follower means. In accordance with the present invention, the follower means 13 are located internally of the roller at a location such that the axis of the roller intersects slide bearing means defined by the follower. The support bar 11 has mounting brackets 15 at its outer ends for rigidly mounting the support bar on a stationary support frame such as shown at 16. In the embodiment shown, the mounting brackets include a base plate 18 having laterally spaced upstanding ears 19 and fasteners 20 extending through the ears 19 and through openings in the ends of the guide bar to rigidly secure the ends of the guide bar to the support frame. The guide bar has end portions 11a which extend oblique to the roller axis and, in order to minimize the overall diameter of the roller required to accommodate the guide bar, the central section 11b of the guide bar preferably extends generally parallel to the roller axis as shown in FIG. 3. The end portions 11a have a noncircular cross-section and preferably have a square cross-section as shown, and the connecting portion 11b can conveniently be in the form of a tube having a cross-section complementary to the rods to receive the same. The tube is rigidly secured as by welding to the end portions 110 to provide a rigid support structure for the roller. As more fully disclosed in the aforementioned U. S. Pat. No. 3,390,823, the end portions 11a of the guide bars are advantageously formed with a longitudinally arcuate configuration defining circular arcs having a common are center indicated at C (FIG. 1

Each of the followers 13 include a hub 23 and the roller is rotatably mounted by bearings 24 on the hub. The bearings 24 are preferably of the anti-friction type and each hub is formed with a cylindrical portion 23a on its outer periphery for receiving the inner races 24a of the bearings. The periphery of each hub is stepped to provide a shoulder 23b for limiting axial movement of the hub in one direction relative to the inner bearing races, and a stop collar, conveniently in the form of a ring nut 26, is connected asby threading at 260 to the other end of the hub to clamp the inner bearing races against the shoulder 23b. A locking washer 25 which is keyed as at 25a to the hub and which has a locking tab 25b adapted to be bent over a projection on the ring nut 26, is provided for locking the ring nut in its adjusted position. Antifriction elements 24b are interposed between the inner races 24a and the outer races 24c of the bearing elements and the latter are received in a reinforcing ring 29 which is secured as by welding to the inside of the roller 10, inwardly of the ends of the roller. The reinforcing ring 29 has a stop shoulder 29a at its inner end and a retaining ring 31 is secured as by fasteners 32 to the outer end of the reinforcing ring to retain the bearing elements against axial movement.

Each hub member 23 has a passage 23c extending therethrough oblique to the axis of the bearings 24 and with its axis generally-tangent to the center line of the arcuate end portions 11a of the guide bar. The passage 230 is conveniently in the form of cylindrical bore and a guide bearing means is disposed in the bore. The guide bearing means is advantageously formed in the manner described in the aforementioned US. Pat. No. 3,390,823 and comprises a plurality of laminations 35a and 35b, each having a noncircular opening 36 therein formed complementary to the cross-section of the end portion of the guide bar. The laminations 35a, 35b are assembled in a stack with the openings 36 in the laminations arranged complementary to the longitudinally arcuate guide bar to define a guide bearing passage of longitudinally arcuate configuration that generally conforms to the end portions of the guide bar. The laminations are held in a stacked assembly by circumferentially spaced fasteners 38 that extend through a clamp ring 39 at the inner end of the stacked assembly and through circumferentially spaced openings in the laminations and are threaded into a retainer plate 41 at the outer end of the stack. The stacked bearing assembly is formed with a cylindrical outer periphery 36a adapted to be snugly received in the passage 23c in the hub member, and the stacked bearing assembly is nonrotatably secured to the hub by fasteners 42 that extend through the retainer ring 41 andinto the hub. With this arrangement, the bearing assembly can be inserted and removed from the hub while the latter is mounted in the roller, to facilitate service and repair or replacement of the guide bearing. In forming the stacked assembly, the laminations can be assembled on a mandrel having a cross-section and longitudinal curvature corresponding to that of the arcuate end portions of the guide bar, and the outer diameter of the laminations thereafter turned to the diameter of the bore 36a in a lathe by rotating the aforedescribed longitudinally arcuate mandrel about its longitudinal center. While the laminations can be formed of various different wear resistant and lubricating materials, they are advantageously formed of plastic with certain of the laminations such as 35a being formed of a polytetrafluoroethylene polymer, for good lubricating characteristics and others of the laminations formed of a wear resistant plastic material such as nylon.

The followers 13 support the roller 10 on the guide bar 11 for longitudinal shifting and tilting movement in a plane of motion which generally parallels a plane through the arcuate end portion of the guide bar and perpendicular to the arc center of these arcuate portions. The noncircular end portions 11a of the guide bar are preferably arranged to provide a pair of opposed faces F and F which generally parallel the plane of motion of the roller and inner and outer faces F and F which define circular arcs concentric with the arc center C. The web W can pass over the roller in various ways and may, for example, have a wrap so that the entering and exiting planes are at right angles to each other or, alternatively, have a wrap in which the entering and exiting planes parallel each other. As shown in FIG. 5, the entering web span W generally parallels the plane of motion of the web guide roller 10 while the exiting span can exit as shown in solid lines in a plane W at right angles to the entering span or, as shown in broken lines at W the web can exit in a plane generally paralleling the entrance web span W The web, as it passes around the roller, applies a substantial lateral force to the roller, that is a force in a direction crosswise of the roller axis. This force is transmitted through the followers to the guide bars. In the present apparatus, the followers including the hub and the guide bearings in the hub are located internally of the roller at a location such that the geometric center of the guide bearing, measured both laterally and longitudinally of the bearing and indicated at X in FIG. 3, is located adjacent the axis A of the roller. With this arrangement, lateral forces applied to the roller, due to web tension and/or other forces acting on the web or roller, are transmitted to the follower in such a manner as to minimize the tendency of the'follower to turn relative to the guide bar. In addition, the annular bearings 24 which support the roller on the follower are preferably located closely adjacent the plane perpendicular to the roller axis and through the center of the guide bearing on the follower.

in web guide apparatus, power-operated mechanisms are commonly employed to effect shifting of the web guide roller in accordance with the position of the web to effect alignment of the web with the desired path of web travel. The operator for effecting relative movement between the roller and the roller support is advantageously mounted internally of the roller. As best shown in FIG. 3, a fluid actuator including a cylinder element 51. and a piston element 52 is located within the roller. The cylinder element is connected as by a swivel connector 53 to a bracket 54 secured to the support bar and the piston element 52 has its rod 52a connected to a swivel fitting 53 connected to the hub of the follower 13 to effect movement of the roller relative to the guide bar in response to extension and retraction of the fluid operator. Fluid is conveniently supplied to the cylinder element through passages in the arcuate end portions 11a of the guide bar. As shown, the end portions of the guide bar have fittings 56 which communicate with a lengthwise passage 57 in theguide bar to a fitting 58 adjacent the inner end of the end portion of the guide bar. The fittings 58 in each end portion are connected as through flexible hoses 59 to a respective end of the cylinder element 51. While the lengthwise passage 57 in each guide bar can be formed in any desired manner, it is conveniently formed by drilling an axial passage in a straight bar and thereafter shaping the bar as by bending to form a longitudinally arcuate configuration. The end portions of the passage 57 are plugged as shown at60 after the passages have been drilled.

Fluid can be reversibly supplied to the cylinder element 51 from any suitable control apparatus which senses the position of the web relative to the path of web travel and applies fluid to the operator, to effect shifting of the roller in a direction to correct deviation of the web from the desired path of web travel. As diagrammatically shown in FIGS. 1 and 5, a web edge sensor 65 is provided for sensing the lateral position of the web and is connected through lines 66 to a control mechanism 67 which operates to reversibly supply fluid to lines 68 leading to the fluid operator. As will be understood, the web edge sensing and control apparatus can be of any suitable type such as electric, pneumatic or mechanical. The web edge sensing and control apparatus diagrammatically shown in FIG. 1 is of the pneumatic-hydraulic type and may, for example, be of the form disclosed in the U.S. Pat. to Robert W. Ott, Jr. No. 3,407,706 patented Oct. 29, 1968. In general, the pneumatic-hydraulic web edge sensing and control apparatus disclosed in that patent includes a four-way reversing valve 71 which reversibly controls the application of fluid from a pump 72 to the control lines 66 leading to the fluid operator 51, 52. Air is supplied from a source such as a blower 73 through a line 74 to a transmitting orifice 65a of the web edge detector 65 and air is also supplied through a restrictor 75 to a diaphragm chamber 76, the diaphragm chamber being otherwise connected through a line 77 to a sensing orifice 65b of the web edge detector 65. The web edge variably interrupts the flow of airfrom the transmitting to the sensing orifice of the web edge detector and modulates the pressure in chamber 76. A diaphragm 79 is responsive to the pressure in the chamber 76 and is connected to the valve 71 to reversibly apply fluid to the cylinder 51. As is well understood in the art, the web edge sensing and control apparatus is arranged to effect longitudinal shifting of the roller 10 in a direction opposite the deviation of the web from the desired path of web travel and the arcuate guide bars and followers produce a lateral tilting of the web as it is shifted along the guide bars to apply a continuous correction to the traveling web in a direction to correct deviation of the web from the desired path of travel.

From the foregoing it is thought that the construction and operation of the web guide roller assembly will be readily understood. The followers 13 support the roller on the end portions 11a of the guide bar for longitudinal shifting and tilting movement about an effective arc center C. The followers 13 are located internally of the roller at a location such that the axis of the roller intersects the guide bearings so that the geometric center of the guide bearings is adjacent the axis of the roller. With this arrangement, lateral forces applied to the roller by the web, due to web tension or other forces acting on the web, are applied generally symmetrically to the guide bearing so that the guide bearing does not tend to turn and bind on the guide rod when the roller is subjected to high lateral thrusts. Moreover, since the followers and operator are located internally of the roller, the web guide roller assembly occupies a minimum of space and requires only a minimum clearance at the sides and ends of the rollers sufficient to accommodate the longitudinal shifting and tilting movement of the roller. Further, by locating the followers internally of the rollers, they are substantially protected by the roller from foreign material.

While a preferred embodiment of the invention has been described, this has been done by way of illustration and not limitation, and I do not wish to be limited except as required by the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a web guide roller assembly for guiding a web moving along a path of web travel relative to a stationary support, the web guide roller assembly including a hollow web guide roller, rigid guide bar means having means for mounting the same on a stationary support, the guide bar means extending through the roller and having first and second end portions extending oblique to the roller axis, first and second guide bar followers each having a guide bearing means slidably and nonrotatably engaging said end portions of the guide bar means, and means rotatably mounting the ends of the roller on the first and second followers, the improvement wherein said first and second followers are disposed internally of said roller at a location such that the axis of the roller intersects the guide bearing means, and said means for rotatably mounting the roller includes first and second annular bearing means disposed internally of said roller and respectively surrounding the first and second followers for rotatably mounting the ends of the roller thereon.

2. A web guide roller assembly according to claim 1 wherein said first and second end portions of the guide bar means have a longitudinally arcuate configuration defining circular arcs having a common are center and i said guide bearing means define longitudinally arcuate guide passages complementary to said longitudinally arcuate end portions of the guide bar means, the center of said longitudinally arcuate guide passages being located adjacent the axis of said roller.

3. A web guide roller assembly according to claim 2 wherein said first and second annular bearings are located adjacent a plane transverse to the roller axis and through the center of the respective guide passage.

4. A web guide roller assembly according to claim 1 including operator means located internally of said roller and operatively connected to said guide bar and to at least one of said followers for shifting the roller along the guide bar.

5. A web guide roller assembly according to claim 1 including a linear fluid actuator having cylinder and piston power members located internally of said roller and having one of said members operatively connected to the guide bar means and the other of the members operatively connected to one of the followers for shifting the roller along the guide bar means and means including passage means in said guide bar for passing fluid to said cylinder member.

6. In a web guide roller assembly including a hollow web guide roller, a rigid guide bar means having means for mounting the same on a stationary support, the guide bar extending through the roller and having end portions of noncircular cross section and longitudinally arcuate configuration extending oblique to the roller axis and defining circular arcs having a common arc center, and means for mounting said roller for axial rotation and for sliding movement along the guide bar, the improvement wherein said roller mounting means includes a pair of hub members located internally of the roller, annular bearing means located internally of said roller between each hub member and the roller supporting the roller for axial rotation relative to the hub members, the hub members each having a passage therethrough extending oblique to the axis of said annular bearing means, guide bearing means in said passage in each hub member defining a longitudinally arcuate guide bearing of noncircular cross section complementary to a respective one of said longitudinally arcuate portions of the guide bar for slidably and nonrotatably mounting the hub on the guide bar, said longitudinally arcuate guide bearings being located internally of said roller at a location such that the axis of the roller intersects said guide bearing means.

7. A web guide roller assembly according to claim 6, wherein said passage in each hub comprises a cylindrical bore extending oblique to the axis of said annular bearings and generally tangent to said arcuate end portions of the bar, said guide bearing means comprising a plurality of laminations each having a noncircular opening complementary to the cross section of the bar,

fastener means extending through the laminations holding the same in an assembled stack with the openings in the laminations arranged to form a longitudinally arcuate guide passage complementary to the longitudinally arcuate end portions of the bar, the stack of laminations having a cylindrical outer periphery disposed in the bore in the hub, and means nonrotatably attaching the stack of laminations to said hub.

8. A web guide roller assembly according to claim 6 including operator means located internally of said roller and operatively connected to said guide bar and one of said hub members for shifting the roller along the guide bar.

9. A web guide roller assembly according to claim 6 including a linear fluid actuator having a cylinder and a piston element located internally of said roller and having one of the elements operatively connected to the guide bar and the other of said elements operatively connected to one of the hub members for shifting the roller along the guide bar, and means including passage means in said guide bar for passing fluid to said cylinder element.

10. A web guide roller assembly comrpising, a hollow web guide roller, a rigid guide bar having means for mounting the bar on a stationary support, the guide bar having a longitudinally arcuate portion of noncircular cross section extending into the roller, a hub member located inwardly of the ends of said roller, annular bearing means located internally of said roller between the hub member and the roller supporting the roller for axial rotation relative to the hub member, said hub member having guide bearing means internally of said annular bearing means defining a longitudinally arcuate guide passage of noncircular cross section complementary to said longitudinally arcuate guide bar for slidably and nonrotatably mounting the hub on the guide bar, said guide bearing means being located internally of said roller at a location such that the axis of the roller intersects said guide passage.

11. A web guide roller assembly according to claim 10 wherein said hub has a cylindrical bore extending therethrough, said bearing means comprising a plurality of flat laminations each having a noncircular opening therein complementary to the cross section of the guide .bar and means securing the laminations in an assembled stack with the openings in the laminations arranged to form a longitudinally arcuate guide passage complementary to said longitudinal guide bar, said stack of laminations having a cylindrical outer periphery disposed in said bore in the hub, and means nonrotatably attaching the stack of laminations to said hub. 

1. In a web guide roller assembly for guiding a web moving along a path of web travel relative to a stationary support, the web guide roller assembly including a hollow web guide roller, rigid guide bar means having means for mounting the same on a stationary support, the guide bar means extending through the roller and having first and second end portions extending oblique to the roller axis, first and second guide bar followers each having a guide bearing means slidably and nonrotatably engaging said end portions of the guide bar means, and means rotatably mounting the ends of the roller on the first and second followers, the improvement wherein said first and second followers are disposed internally of said roller at a location such that the axis of the roller intersects the guide bearing means, and said means for rotatably mounting the roller includes first and second annular bearing means disposed internally of said roller and respectively surrounding the first and second followers for rotatably mounting the ends of the roller thereon.
 2. A web guide roller assembly according to claim 1 wherein said first and second end portions of the guide bar means have a longitudinally arcuate configuration defining circular arcs having a common arc center and said guide bearing means define longitudinally arcuate guide passages complementary to said longitudinally arcuate end portions of the guide bar means, the center of said longitudinally arcuate guide passages being located adjacent the axis of said roller.
 3. A web guide roller assembly according to claim 2 wherein said first and second annular bearings are located adjacent a plane transverse to the roller axis and through the center of the respective guide passage.
 4. A web guide roller assembly according to claim 1 including operator means located internally of said roller and operatively connected to said guide bar and to at least one of said followers for shifting the roller along the guide bar.
 5. A web guide roller assembly according to claim 1 including a linear fluid actuator having cylinder and piston power members located internally of said roller and having one of said members operatively connected to the guide bar means and the other of the members operatively connected to one of the followers for shifting the roller along the guide bar means and means including passage means in said guide bar for passing fluid to said cylinder member.
 6. In a web guide roller assembly including a hollow web guide roller, a rigid guide bar means having means for mounting the same on a stationary support, the guide bar extending through the roller and having end portions of noncircular cross section and longitudinally arcuate configuration extending oblique to the roller axis and defining circular arcs having a common arc center, and means for mounting said roller for axial rotation and for sliding movement along the guide bar, the improvement wherein said roller mounting means includes a pair of hub members located internally of the roller, annular bearing means located internally of said roller between each hub member and the roller supporting the roller for axial rotation relative to the hub members, the hub members each having a passage therethrough extending oblique to the axis of said annular bearing means, guide bearing means in said passage in each hub member defining a longitudinally arcuate guide bearing of noncircular cross section complementary to a respective one of said longitudinally arcuate portions of the guide bar for Slidably and nonrotatably mounting the hub on the guide bar, said longitudinally arcuate guide bearings being located internally of said roller at a location such that the axis of the roller intersects said guide bearing means.
 7. A web guide roller assembly according to claim 6, wherein said passage in each hub comprises a cylindrical bore extending oblique to the axis of said annular bearings and generally tangent to said arcuate end portions of the bar, said guide bearing means comprising a plurality of laminations each having a noncircular opening complementary to the cross section of the bar, fastener means extending through the laminations holding the same in an assembled stack with the openings in the laminations arranged to form a longitudinally arcuate guide passage complementary to the longitudinally arcuate end portions of the bar, the stack of laminations having a cylindrical outer periphery disposed in the bore in the hub, and means nonrotatably attaching the stack of laminations to said hub.
 8. A web guide roller assembly according to claim 6 including operator means located internally of said roller and operatively connected to said guide bar and one of said hub members for shifting the roller along the guide bar.
 9. A web guide roller assembly according to claim 6 including a linear fluid actuator having a cylinder and a piston element located internally of said roller and having one of the elements operatively connected to the guide bar and the other of said elements operatively connected to one of the hub members for shifting the roller along the guide bar, and means including passage means in said guide bar for passing fluid to said cylinder element.
 10. A web guide roller assembly comrpising, a hollow web guide roller, a rigid guide bar having means for mounting the bar on a stationary support, the guide bar having a longitudinally arcuate portion of noncircular cross section extending into the roller, a hub member located inwardly of the ends of said roller, annular bearing means located internally of said roller between the hub member and the roller supporting the roller for axial rotation relative to the hub member, said hub member having guide bearing means internally of said annular bearing means defining a longitudinally arcuate guide passage of noncircular cross section complementary to said longitudinally arcuate guide bar for slidably and nonrotatably mounting the hub on the guide bar, said guide bearing means being located internally of said roller at a location such that the axis of the roller intersects said guide passage.
 11. A web guide roller assembly according to claim 10 wherein said hub has a cylindrical bore extending therethrough, said bearing means comprising a plurality of flat laminations each having a noncircular opening therein complementary to the cross section of the guide bar and means securing the laminations in an assembled stack with the openings in the laminations arranged to form a longitudinally arcuate guide passage complementary to said longitudinal guide bar, said stack of laminations having a cylindrical outer periphery disposed in said bore in the hub, and means nonrotatably attaching the stack of laminations to said hub. 